A DTV receiving system for processing digital broadcast data includes a tuner for receiving a broadcast signal from a DTV transmitter, an equalizer for compensating channel distortion of the broadcast signal using the known data sequences, and a decoder for decoding the equalized broadcast signal, wherein the broadcast signal results from generating a first data group including first, second and third regions; interleaving the first data group to generate a second data group including fourth, fifth and sixth regions; and trellis encoding the second data group.